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The aim of this investigation was to compare the effect of three different stretchers (two powered and one manual) on the biomechanical and psychophysical demands experienced by paramedics when performing routine stretcher handling activities. Eight experienced paramedics performed stretcher raising, lowering, unloading and loading tasks. Video data of task performance and static force requirements were recorded and input into a posture matching program with a quasi-static linked segment model (3DMatch) to compute peak and cumulative L4/L5 compression and shear forces and shoulder moments during each activity. Ratings of perceived exertion (RPE) were recorded from paramedics upon the completion of each task. Use of powered stretchers with load assist functionality reduced the demands on paramedics. Peak L4/L5 forces were reduced by 13-62% and 58-93% for compression and shear respectively when using powered stretchers to perform routine stretcher handling activities. Shoulder flexor moments and RPE scores were reduced by 16-95% and 29-60% respectively when using the powered stretchers compared to the manual stretcher. However, cumulative forces showed mixed results. Although powered stretcher use decreased peak forces, loading and unloading a powered stretcher took 1.5 to 3.4 times longer then when using the manual stretcher, which may explain the mixed results regarding cumulative forces. Based on the RPE scores, paramedics preferred power stretchers relative to the manual stretcher. This study demonstrates that powered stretchers can reduce peak biomechanical and psychophysical exposures associated with the development of musculoskeletal disorder (MSD) during routine stretcher handling activities with minimal increases in cumulative exposures., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objective: To gather information on the (a) types of wearable sensors, particularly personal activity monitors, currently used by occupational safety and health (OSH) professionals; (b) potential benefits of using such technologies in the workplace; and (c) perceived barriers preventing the widespread adoption of wearable sensors in industry., Background: Wearable sensors are increasingly being promoted as a means to improve employee health and well-being, and there is mounting evidence supporting their use as exposure assessment and personal health tools. Despite this, many workplaces have been hesitant to adopt these technologies., Methods: An electronic survey was emailed to 28,428 registered members of the American Society of Safety Engineers (ASSE) and 1,302 professionals certified by the Board of Certification in Professional Ergonomics (BCPE)., Results: A total of 952 valid responses were returned. Over half of respondents described being in favor of using wearable sensors to track OSH-related risk factors and relevant exposure metrics at their respective workplaces. However, barriers including concerns regarding employee privacy/confidentiality of collected data, employee compliance, sensor durability, the cost/benefit ratio of using wearables, and good manufacturing practice requirements were described as challenges precluding adoption., Conclusion: The broad adoption of wearable technologies appears to depend largely on the scientific community's ability to successfully address the identified barriers., Application: Investigators may use the information provided to develop research studies that better address OSH practitioner concerns and help technology developers operationalize wearable sensors to improve employee health and well-being.

Background: Alternative methods of accessing the internet and performing computing-related work tasks are becoming common, e.g., using tablets or standing workstations. Few studies examine postural differences while using these alternative methods., Objective: To assess neck and upper limb kinematics while using a tablet, laptop and desktop computer (sitting and standing)., Methods: Differences in neck flexion/extension, lateral flexion, rotation; elbow flexion/extension; wrist flexion/extension, radial/ulnar deviation; and shoulder elevation in 30 participants were assessed in four conditions, three in sitting (tablet, laptop and desktop computer) and one in standing (desktop computer). Three-dimensional motion capture recorded posture variables during an editing task. Differences between variables were determined using one-way ANOVA with Bonferroni post-hoc tests., Results: Compared to the desktop (sitting), tablet and laptop use resulted in increased neck flexion (mean difference tablet 16.92°, 95% CI 12.79-21.04; laptop 10.92, 7.86-13.97, P < 0.001) and shoulder elevation (right; tablet 10.29, 5.27-15.11; laptop 7.36, 3.72-11.01, P < 0.001). There were no meaningful posture differences between the sitting and standing desktop., Conclusions: These findings suggest that using a tablet or laptop may increase neck flexion, potentially increasing posture strain. Regular users of tablets/laptops should consider adjustments in their posture, however, further research is required to determine whether posture adjustments prevent or reduce musculoskeletal symptoms.

The aim of this study was to perform an ergonomic analysis of a material handling task by combining a subtask video analysis and a RULA computation, implemented continuously through a motion capture system combining inertial sensors and electrogoniometers. Five workers participated to the experiment. Seven inertial measurement units, placed on the worker's upper body (pelvis, thorax, head, arms, forearms), were implemented through a biomechanical model of the upper body to continuously provide trunk, neck, shoulder and elbow joint angles. Wrist joint angles were derived from electrogoniometers synchronized with the inertial measurement system. Worker's activity was simultaneously recorded using video. During post-processing, joint angles were used as inputs to a computationally implemented ergonomic evaluation based on the RULA method. Consequently a RULA score was calculated at each time step to characterize the risk of exposure of the upper body (right and left sides). Local risk scores were also computed to identify the anatomical origin of the exposure. Moreover, the video-recorded work activity was time-studied in order to classify and quantify all subtasks involved into the task. Results showed that mean RULA scores were at high risk for all participants (6 and 6.2 for right and left sides respectively). A temporal analysis demonstrated that workers spent most part of the work time at a RULA score of 7 (right: 49.19 ± 35.27%; left: 55.5 ± 29.69%). Mean local scores revealed that most exposed joints during the task were elbows, lower arms, wrists and hands. Elbows and lower arms were indeed at a high level of risk during the total time of a work cycle (100% for right and left sides). Wrist and hands were also exposed to a risky level for much of the period of work (right: 82.13 ± 7.46%; left: 77.85 ± 12.46%). Concerning the subtask analysis, subtasks called 'snow thrower', 'opening the vacuum sealer', 'cleaning' and 'storing' have been identified as the most awkward for right and left sides given mean RULA scores and percentages of time spent at risky levels. Results analysis permitted to suggest ergonomic recommendations for the redesign of the workstation. Contributions of the proposed innovative system dedicated to physical ergonomic assessment are further discussed., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The distribution of exposure to biomechanical and organisational job stressors (BOJS) and associations with employment withdrawal (antenatal leave, unemployment) was examined in a case-control study of 1114 pregnant workers in California. We performed descriptive and multivariate logistic and multinomial regression analyses. At pregnancy onset, 57% were exposed to one or more biomechanical stressors, including frequent bending, heavy lifting and prolonged standing. One-third were simultaneously exposed to BOJS. Exposure to biomechanical stressors declined as pregnancy progressed and cessation often (41%) coincided with employment withdrawal (antenatal leave and unemployment). In multivariate modelling, whether we adjusted for or considered organisational stressors as coincident exposures, results showed that pregnant workers exposed to biomechanical stressors had increased employment withdrawal compared to the unexposed. Work schedule accommodations moderate this association. Paid antenatal leave, available to few US women, was an important strategy for mitigating exposure to BOJS. Implications for science and policy are discussed. Practitioner Summary: This case-control study showed that exposure to biomechanical stressors decline throughout pregnancy. Antenatal leave was an important strategy used for mitigating exposure among sampled California women with access to paid benefits. Employment withdrawal among workers exposed to BJOS may be reduced by proactive administrative and engineering efforts applied early in pregnancy.

Objective: The aim of this study was to determine and verify the optimal location of the motion axis (MA) for the seat of a dynamic office chair., Background: A dynamic seat that supports pelvic motion may improve physical well-being and decrease the risk of sitting-associated disorders. However, office work requires an undisturbed view on the work task, which means a stable position of the upper trunk and head. Current dynamic office chairs do not fulfill this need. Consequently, a dynamic seat was adapted to the physiological kinematics of the human spine., Method: Three-dimensional motion tracking in free sitting helped determine the physiological MA of the spine in the frontal plane. Three dynamic seats with physiological, lower, and higher MA were compared in stable upper body posture (thorax inclination) and seat support of pelvic motion (dynamic fitting accuracy). Spinal kinematics during sitting and walking were compared., Results: The physiological MA was at the level of the 11th thoracic vertebra, causing minimal thorax inclination and high dynamic fitting accuracy. Spinal motion in active sitting and walking was similar., Conclusion: The physiological MA of the seat allows considerable lateral flexion of the spine similar to walking with a stable upper body posture and a high seat support of pelvic motion., Application: The physiological MA enables lateral flexion of the spine, similar to walking, without affecting stable upper body posture, thus allowing active sitting while focusing on work., (© 2016, Human Factors and Ergonomics Society.)

Objective: We seek to develop a new approach for analyzing the physical demands of highly variable lifting tasks through an adaptation of the Revised NIOSH (National Institute for Occupational Safety and Health) Lifting Equation (RNLE) into a Variable Lifting Index (VLI)., Background: There are many jobs that contain individual lifts that vary from lift to lift due to the task requirements. The NIOSH Lifting Equation is not suitable in its present form to analyze variable lifting tasks., Method: In extending the prior work on the VLI, two procedures are presented to allow users to analyze variable lifting tasks. One approach involves the sampling of lifting tasks performed by a worker over a shift and the calculation of the Frequency Independent Lift Index (FILI) for each sampled lift and the aggregation of the FILI values into six categories. The Composite Lift Index (CLI) equation is used with lifting index (LI) category frequency data to calculate the VLI. The second approach employs a detailed systematic collection of lifting task data from production and/or organizational sources. The data are organized into simplified task parameter categories and further aggregated into six FILI categories, which also use the CLI equation to calculate the VLI., Results: The two procedures will allow practitioners to systematically employ the VLI method to a variety of work situations where highly variable lifting tasks are performed., Conclusions: The scientific basis for the VLI procedure is similar to that for the CLI originally presented by NIOSH; however, the VLI method remains to be validated., Application: The VLI method allows an analyst to assess highly variable manual lifting jobs in which the task characteristics vary from lift to lift during a shift., (© 2015, Human Factors and Ergonomics Society.)

The size and shape of users are an important consideration for many products and environments. Designers and engineers in many disciplines must often accommodate these attributes to meet objectives such as fit and safety. When practitioners have academic training in addressing these issues, it is typically through courses in Human Factors/Ergonomics (HF/E). This paper investigates education related to physical accommodation and offers suggestions for improvement. A survey was conducted wherein 21 instructors at 18 universities in the United States provided syllabi for 29 courses, which were analysed to determine topics related to anthropometry and resources used for the courses. The results show that within the U.S., anthropometry is covered in the majority of courses discussing physical ergonomics, but important related concepts were often omitted (e.g., digital human modelling, multivariate accommodation and variability across global populations). Curricula could be improved by incorporating more accurate anthropometry, multivariate problems and interactive online tools., Practitioner Summary: This paper describes a study investigating collegiate ergonomics courses within the U.S. in the area of physical accommodation. Course schedules and texts were studied for their treatment of several topics related to accommodating the spatial requirements (anthropometry) of users. Recommendations are made for improving course curricula.

Objective: We examined magnitude preference, subjective discomfort, and spine posture during prolonged simulated driving with a self-selected amount of lumbar support., Background: The general use of lumbar supports has been associated with decreased reports of low-back pain during driving exposures; however, minimal data exist regarding occupant magnitude preference., Method: Participants chose between five discrete levels of lumbar support (0-4 cm). Time-varying postural and discomfort responses were then monitored throughout 2 hr of simulated driving., Results: There were no significant effects of gender or time on posture. Women preferred larger amounts of support than men (3.25 cm ± 0.71 and 2.56 cm ± 0.88, respectively, p = .048). All participants exhibited significant increases (p = .003) in pelvic discomfort throughout the 2-hr trial regardless of the level of support chosen. Discomfort related to various aspects of the lumbar support increased significantly over time. Retrospectively, no participants desired a setting beyond 4 cm, and the majority of respondents indicate had they been able to change their initial selection, they would choose a setting between 2 and 3 cm., Conclusion: The results suggest that occupants would prefer increasing the excursion capability of automobile lumbar supports beyond 2 cm., Application: Excursion capability and adjustability of automobile lumbar supports are important features to better meet end-user preference and to reducing lumbar flexion in sitting., (© 2015, Human Factors and Ergonomics Society.)

Background: Ophthalmologists report a high prevalence of work-related musculoskeletal symptoms, particularly of the neck and shoulders. Improving the design of equipment used in the clinical environment may reduce exposures to physical risk factors (e.g., sustained muscular exertions and non-neutral postures) associated with neck and shoulder pain among ophthalmologists., Purpose: To compare estimates of neck and shoulder muscle activity and upper arm posture during use of conventional and alternative examination equipment common in clinical ophthalmologic practice., Methods: Fifteen ophthalmologists performed one mock clinical examination using conventional equipment and one mock clinical examination using alternative equipment with the potential to reduce exposure to sustained muscular exertions and non-neutral upper arm postures. The alternative equipment included a slit-lamp biomicroscope with inclined viewing oculars, adjustable elbow supports, and a wider table-top with more room for supporting the arms in comparison to the conventional slit-lamp biomicroscope. A wireless binocular indirect ophthalmoscope was also evaluated that had a more even weight distribution than the conventional design. Measurements of upper trapezius and anterior deltoid muscle activity, upper arm posture, and perceived usability were used to compare the conventional and alternative equipment., Results: In comparison to the conventional slit lamp biomicroscope, the alternative slit lamp biomicroscope led to (i) 12% to 13% reductions in upper trapezius muscle activity levels, (ii) a 9% reduction in left anterior deltoid muscle activity levels, and (iii) a 15% reduction in the percentage of work time spent with the left upper arm elevated in positions greater than 60°. In addition, participants rated the comfort and adjustability of both the alternative slit lamp biomicroscope and binocular indirect ophthalmoscope more favorably than the conventional equipment., Conclusions: The results suggest that the alternative slit-lamp biomicroscope may help to reduce overall muscular demands and non-neutral postures of the neck and shoulder region among ophthalmologists., Competing Interests: Conflict of Interest Statement The authors declare no conflict of interest. Equipment used in this study was obtained from Haag-Streit USA/Reliance Medical Products, Mason, OH, USA. Haag-Streit USA/Reliance Medical Products had no role in the design or conduct of this research.